1. Field of the Invention
The present invention relates to a liquid ejecting apparatus for ejecting liquid to a target. More particularly, the present invention relates to a liquid ejecting apparatus for managing a remaining amount of waste liquid, which is accommodated in an accommodating section, discharged from a liquid ejecting head in order to recover liquid-ejection ability of the liquid ejecting head.
2. Description of Related Art
In a liquid ejecting apparatus such as an ink-jet type recording apparatus for ejecting liquid to a target, a cleaning operation during which liquid is discharged or absorbed from a liquid ejecting head is performed separately from ejecting liquid to the target in order to prevent a clogging of the head or to recover liquid-ejection ability of the head. The liquid discharged from the head during the cleaning operation is accommodated in a waste liquid absorber.
A remaining amount of waste liquid in the waste liquid absorber is computed whenever a recovery operation is performed. In this way, when the computed remaining amount exceeds a certain threshold value, the apparatus is controlled to display an error message that requires maintenance or to prohibit the recovery operation. In this case, some of the waste liquid is evaporated as time has elapsed after the waste liquid has been discharged. Therefore, it is possible to accurately compute the remaining amount of waste liquid in the waste liquid absorber by computing an evaporation amount of the waste liquid depending on an elapsed time.
By the way, to measure an elapsed time for computation of evaporation amount of waste liquid, there is a method by which a current time is acquired from a built-in clock every recovery operation and then an elapsed time is measured by difference between the current time and the previous acquired time. However, an accurate time cannot be acquired when electric power is not supplied to the built-in clock. Thus, the apparatus is controlled so as not to compute the evaporation amount of waste liquid when the built-in clock has stopped, the built-in clock had stopped before, or setting of the built-in clock has been changed. In this way, it is prevented that the evaporation amount is inaccurately computed, thereby being capable of managing the remaining amount of waste liquid suitably. This technique is known from, e.g., Japanese Patent Laid-Open No. 1997-104121.
However, in the conventional art, since an evaporation amount of waste liquid cannot be computed when a power source has been turned off for a long time, a remaining amount is computed higher than a real amount. Therefore, there was a problem that a waste liquid absorber cannot be utilized maximally when trying to prevent waste liquid from leaking outside the apparatus.